1. Field of the Invention
The present invention relates to a compound semiconductor and its manufacturing method, and a thermoelectric conversion device using the same.
2. Description of the Related Art
A compound semiconductor is a compound that is composed of elements from two or more different elements, not a single element such as silicon, germanium and so on, and acts as a semiconductor. Currently, various kinds of compound semiconductors have been developed and used in various industrial fields. For example, the compound semiconductor is representatively used to a solar cell or a light emitting device including a light emitting diode or a laser diode, using the photoelectric conversion effect, a thermoelectric conversion device using the Feltier Effect, and so on.
Among them, the thermoelectric conversion device is applied to thermoelectric power generation, thermoelectric cooling and so on. For example, thermoelectric power generation is a type of power generation that converts thermal energy into electric energy using a thermoelectromotive force caused by temperature difference in a thermoelectric conversion device.
The energy conversion efficiency of the thermoelectric conversion device is determined depending on Seebeck coefficient, electrical conductivity and thermal conductivity of a thermoelectric conversion material. More specifically, the energy conversion efficiency of the thermoelectric conversion material is in proportion to the square of Seebeck coefficient and the electrical conductivity, and in inverse proportion to the thermal conductivity. Therefore, it is required that the development of a thermoelectric conversion material having high Seebeck coefficient or high electrical conductivity or low thermal conductivity so as to improve the energy conversion efficiency of a thermoelectric conversion device.